Questions about decompression and deep extraction
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Deep drawing of 565 degrees has been successfully applied abroad. The design base point is 565.6 degrees. A large part of the colloid has entered the vacuum gas oil. However, I have always wanted to understand the transportation problem of vacuum residual oil. The viscosity is high and the asphaltene is high. The coking device must use a large circulation ratio and the furnace must clean coke online. The processing is difficult. I wonder if the teacher has a deep understanding of this. Please enlighten me.
After deep pulling, a large amount of heavy distillate oil was obtained. This part of the distillate oil is not suitable for hydrocracking, so it can only be catalytically cracked. In this way, the catalytic cracking feed is much worse than when it was cut to 525 degrees, so more catalytic cracking oil is obtained. The slurry requires a large amount of external rejection. Everyone knows that the catalytic cracking oil slurry is difficult to handle, so it is sent to the coking device. The catalytic cracking oil slurry has a low viscosity and is mixed with the reduced residue to improve the fluidity of the feed. In this way, there is no need to have a large circulation ratio, and only an appropriate circulation ratio is required. Another possibility is that the obtained distillate is first hydrorefined and then hydrocracked. In this way, the treatment of vacuum residue oil is more difficult, but viscosity reducing devices can be advanced to obtain viscosity-reduced oil that can be used as fuel oil or further coked. The residual oil can also be treated directly with solvent deasphalting. Of course, it will be more difficult if the vacuum residue is directly fed into the delayed coking device, but if fluid coking is used, there should not be too many problems. If delayed coking is carried out directly, optimized multi-point steam injection needs to be used to improve the heat transfer of the heating furnace.
After decompression extraction, there is catalytic raw material pretreatment, and the catalytic heavy cycle oil needs to be returned to the catalytic raw material pretreatment, or the vacuum residual oil is diluted. However, the distance between normal and vacuum pressure and coking is 1.5 kilometers. Can deep extraction be carried out?
How far is your catalytic cracking unit from normal and vacuum pressure? If the catalytic cycle oil can be mixed with the reduced residue in time, there should not be any big problems in transportation.
Then you can completely treat the catalytic cracking external oil slurry and mix it with slag reduction, and then proceed to coking.
It is no problem to achieve thermal combination and transportation. The quality of wax oil has a lot to do with the properties of crude oil. Whether it is for catalysis or hydrogenation, when the properties deteriorate and affect the downstream equipment, the extraction depth should be reduced.